edns-subnet: fix NULL_AFTER_DEREF on subnetmod (#1297)

Found by static analyzer svace.
Static analyzer message: Redundant comparison with a NULL value at subnetmod.c:236 for pointer 'sn_env->subnet_msg_cache',
which was dereferenced at slabhash.c:228 by passing as 1st parameter to function 'slabhash_setmarkdel' at subnetmod.c:235.

Moved usage of sn_env->subnet_msg_cache in slabhash_setmarkdel after checking.

Signed-off-by: Konstantin Kamanin <bewflast@gmail.com>

diff --git a/edns-subnet/subnetmod.c b/edns-subnet/subnetmod.c
index ead720f340063d655e2e28e642bb97f6dba02557..ef70098bebac2bbca43c47b03d537e598f4d2b89 100644 (file)
--- a/edns-subnet/subnetmod.c
+++ b/edns-subnet/subnetmod.c
@@ -232,13 +232,13 @@ subnetmod_init(struct module_env *env, int id)
                HASH_DEFAULT_STARTARRAY, env->cfg->msg_cache_size,
                msg_cache_sizefunc, query_info_compare, query_entry_delete,
                subnet_data_delete, NULL);
-       slabhash_setmarkdel(sn_env->subnet_msg_cache, &subnet_markdel);
        if(!sn_env->subnet_msg_cache) {
                log_err("subnetcache: could not create cache");
                free(sn_env);
                env->modinfo[id] = NULL;
                return 0;
        }
+       slabhash_setmarkdel(sn_env->subnet_msg_cache, &subnet_markdel);
        /* whitelist for edns subnet capable servers */
        sn_env->whitelist = ecs_whitelist_create();
        if(!sn_env->whitelist ||